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/* SPDX-License-Identifier: LGPL-2.1-or-later */
#include "sd-device.h"
#include "device-private.h"
#include "device-util.h"
#include "string-util.h"
#include "battery-util.h"
#define BATTERY_LOW_CAPACITY_LEVEL 5
static int device_is_power_sink(sd_device *device) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
bool found_source = false, found_sink = false;
sd_device *parent;
int r;
assert(device);
/* USB-C power supply device has two power roles: source or sink. See,
* https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-typec */
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_subsystem(e, "typec", true);
if (r < 0)
return r;
r = sd_device_get_parent(device, &parent);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_parent(e, parent);
if (r < 0)
return r;
FOREACH_DEVICE(e, d) {
const char *val;
r = sd_device_get_sysattr_value(d, "power_role", &val);
if (r < 0) {
if (r != -ENOENT)
log_device_debug_errno(d, r, "Failed to read 'power_role' sysfs attribute, ignoring: %m");
continue;
}
if (strstr(val, "[source]")) {
found_source = true;
log_device_debug(d, "The USB type-C port is in power source mode.");
} else if (strstr(val, "[sink]")) {
found_sink = true;
log_device_debug(d, "The USB type-C port is in power sink mode.");
}
}
if (found_sink)
log_device_debug(device, "The USB type-C device has at least one port in power sink mode.");
else if (!found_source)
log_device_debug(device, "The USB type-C device has no port in power source mode, assuming the device is in power sink mode.");
else
log_device_debug(device, "All USB type-C ports are in power source mode.");
return found_sink || !found_source;
}
static bool battery_is_discharging(sd_device *d) {
const char *val;
int r;
assert(d);
r = sd_device_get_sysattr_value(d, "scope", &val);
if (r < 0) {
if (r != -ENOENT)
log_device_debug_errno(d, r, "Failed to read 'scope' sysfs attribute, ignoring: %m");
} else if (streq(val, "Device")) {
log_device_debug(d, "The power supply is a device battery, ignoring device.");
return false;
}
r = device_get_sysattr_bool(d, "present");
if (r < 0)
log_device_debug_errno(d, r, "Failed to read 'present' sysfs attribute, assuming the battery is present: %m");
else if (r == 0) {
log_device_debug(d, "The battery is not present, ignoring the power supply.");
return false;
}
/* Possible values: "Unknown", "Charging", "Discharging", "Not charging", "Full" */
r = sd_device_get_sysattr_value(d, "status", &val);
if (r < 0) {
log_device_debug_errno(d, r, "Failed to read 'status' sysfs attribute, assuming the battery is discharging: %m");
return true;
}
if (!streq(val, "Discharging")) {
log_device_debug(d, "The battery status is '%s', assuming the battery is not used as a power source of this machine.", val);
return false;
}
return true;
}
int on_ac_power(void) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
bool found_ac_online = false, found_discharging_battery = false;
int r;
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_subsystem(e, "power_supply", true);
if (r < 0)
return r;
FOREACH_DEVICE(e, d) {
/* See
* https://github.com/torvalds/linux/blob/4eef766b7d4d88f0b984781bc1bcb574a6eafdc7/include/linux/power_supply.h#L176
* for defined power source types. Also see:
* https://docs.kernel.org/admin-guide/abi-testing.html#abi-file-testing-sysfs-class-power */
const char *val;
r = sd_device_get_sysattr_value(d, "type", &val);
if (r < 0) {
log_device_debug_errno(d, r, "Failed to read 'type' sysfs attribute, ignoring device: %m");
continue;
}
/* Ignore USB-C power supply in source mode. See issue #21988. */
if (streq(val, "USB")) {
r = device_is_power_sink(d);
if (r <= 0) {
if (r < 0)
log_device_debug_errno(d, r, "Failed to determine the current power role, ignoring device: %m");
else
log_device_debug(d, "USB power supply is in source mode, ignoring device.");
continue;
}
}
if (streq(val, "Battery")) {
if (battery_is_discharging(d)) {
found_discharging_battery = true;
log_device_debug(d, "The power supply is a battery and currently discharging.");
}
continue;
}
r = device_get_sysattr_unsigned(d, "online", NULL);
if (r < 0) {
log_device_debug_errno(d, r, "Failed to query 'online' sysfs attribute, ignoring device: %m");
continue;
} else if (r > 0) /* At least 1 and 2 are defined as different types of 'online' */
found_ac_online = true;
log_device_debug(d, "The power supply is currently %s.", r > 0 ? "online" : "offline");
}
if (found_ac_online) {
log_debug("Found at least one online non-battery power supply, system is running on AC.");
return true;
} else if (found_discharging_battery) {
log_debug("Found at least one discharging battery and no online power sources, assuming system is running from battery.");
return false;
} else {
log_debug("No power supply reported online and no discharging battery found, assuming system is running on AC.");
return true;
}
}
/* Get the list of batteries */
int battery_enumerator_new(sd_device_enumerator **ret) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
int r;
assert(ret);
r = sd_device_enumerator_new(&e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_subsystem(e, "power_supply", /* match = */ true);
if (r < 0)
return r;
r = sd_device_enumerator_allow_uninitialized(e);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_sysattr(e, "type", "Battery", /* match = */ true);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_sysattr(e, "present", "1", /* match = */ true);
if (r < 0)
return r;
r = sd_device_enumerator_add_match_sysattr(e, "scope", "Device", /* match = */ false);
if (r < 0)
return r;
*ret = TAKE_PTR(e);
return 0;
}
/* Battery percentage capacity fetched from capacity file and if in range 0-100 then returned */
int battery_read_capacity_percentage(sd_device *dev) {
int battery_capacity, r;
assert(dev);
r = device_get_sysattr_int(dev, "capacity", &battery_capacity);
if (r < 0)
return log_device_debug_errno(dev, r, "Failed to read/parse POWER_SUPPLY_CAPACITY: %m");
if (battery_capacity < 0 || battery_capacity > 100)
return log_device_debug_errno(dev, SYNTHETIC_ERRNO(ERANGE), "Invalid battery capacity");
return battery_capacity;
}
/* If a battery whose percentage capacity is <= 5% exists, and we're not on AC power, return success */
int battery_is_discharging_and_low(void) {
_cleanup_(sd_device_enumerator_unrefp) sd_device_enumerator *e = NULL;
bool unsure = false, found_low = false;
int r;
/* We have not used battery capacity_level since value is set to full
* or Normal in case ACPI is not working properly. In case of no battery
* 0 will be returned and system will be suspended for 1st cycle then hibernated */
r = on_ac_power();
if (r < 0)
log_debug_errno(r, "Failed to check if the system is running on AC, assuming it is not: %m");
if (r > 0)
return false;
r = battery_enumerator_new(&e);
if (r < 0)
return log_debug_errno(r, "Failed to initialize battery enumerator: %m");
FOREACH_DEVICE(e, dev) {
int level;
level = battery_read_capacity_percentage(dev);
if (level < 0) {
unsure = true;
continue;
}
if (level > BATTERY_LOW_CAPACITY_LEVEL) /* Found a charged battery */
return false;
found_low = true;
}
/* If we found a battery whose state we couldn't read, don't assume we are in low battery state */
if (unsure) {
log_debug("Found battery with unreadable state, assuming not in low battery state.");
return false;
}
/* If found neither charged nor low batteries, assume that we aren't in low battery state */
return found_low;
}
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